Earning $30.00 per month with a website is very much achievable. You can start a website on a high paying niche such as health,insurance lawyer etc and place Adsense on the website.
Then you can use twitter to drive targeted traffic to your website.
Do note though that you will not get paid the money from Adsense until you reach $100.00 so it will take you 4 months before you get a payment.